Notes from the field: repeat syphilis infection and HIV coinfection among men who have sex with men--Baltimore, Maryland, 2010-2011.

Syphilis diagnoses in the United States have increased substantially over the past decade, and most cases occurred among men who have sex with men (MSM). Nationally, rates of primary and secondary (P&S) syphilis reported among men increased, from 3.0 cases per 100,000 population in 2001 to 8.2 in 2011. In 2011, approximately 72% of P&S syphilis cases occurred among MSM*, among whom new diagnoses of human immunodeficiency virus (HIV) infection have increased in recent years. Infection with syphilis increases the likelihood of acquiring and transmitting HIV; moreover, the occurrence of syphilis in an HIV-infected person is an indication of behavior that might increase the likelihood of HIV transmission. The population of Baltimore, Maryland, is particularly affected by syphilis and HIV. In 2011, the Baltimore metropolitan statistical area (MSA) had the second highest rate of reported cases of P&S syphilis (11.4 per 100,000 population) and the sixth highest estimated rate of diagnoses of HIV infection (33.8 per 100,000 population) compared with other MSAs in the United States. Local public health officials have noted a subpopulation of MSM diagnosed with repeat syphilis infection; they believe that this subpopulation might bear a disproportionate burden of both syphilis and HIV infection and that intensifying syphilis and HIV prevention efforts among this subpopulation might reduce syphilis and HIV transmission overall in the Baltimore area.